Syringe

ABSTRACT

A syringe having a one piece plastic cannula, piston and plunger.

Unlted States Patent [1 1 3,906,947 Cloyd Sept. 23, 1975 [54] SYRINGE 2,539,510 1/1951 Friden 128/220 22 [76] Inventor: Harold s. Cloyd, 3244 Willis 51., 5 4 Erie, Pa. 3,378,008 4/1968 Ogle 128/220 [22] Filed: FOREIGN PATENTS 0 R APPLICATIONS 21 App]. No.: 98,225 1,333,235 6/1963 France 128/218 1,228,933 9/1960 France 128/218 52 U.S. Cl. 128/237; 128/218 P; 128/220 51 1111.01 A61M 1/00 PmfWY "f' Gaude [58] Field of Search 128/237, 234, 213, 215, fl- Yasko Attorney, Agent, or Hammar [56] Refenences Cited 57 ABSTRACT UNITED STATES PATENTS A syringe having a one piece plastic cannula, piston 497,250 5/1893 Oliver 128/237 and plunger 2,448,898 9/1948 Lockhal't 128/220 2,512,568 6/1950 Saffir 128/221 X 6 Claims, 3 Drawing Figures US Patent Sept. 23,1975

FIG.\

INVENTOR ATTORNEY SYRINGE This invention is a syringe which consists essentially of three molded plastic parts; a plunger, piston and cannula; a barrel; and a cap for the cannula.

In the drawing,

FIG. 1 is a longitudinal section on line 1-l of FIG. 3 through a preferred form of syringe,

FIG. 2 is an enlarged fragmentary section of the piston, and

FIG. 3 is a section on line 3-3 of FIG. 1.

The barrel of the syringe is a fluid containing vial 1 closed at one end 2 and having a finger gripping flange 3 at its opposite or open end. The vial may be made of one of the flexible plastics such as polypropylene or other plastic compatible with the fluid contents.

The cannula 4, likewise of molded plastic, has its fluid receiving end 5 presented to the closed end of the barrel and has its fluid discharging end 6 projecting outside the open end of the barrel. The fluid discharging end is normally closed or protected by a cap 7 which may be of any suitable plastic or other material. The fluid receiving end of the cannula is integral with a circular end wall 8 having an integral hollow cylindri cal peripheral flange 9 extending toward the open end of the barrel. Integral with the inner edge of the flange 9 is the inner edge 10 of an annular flange 1 1 extending outwardly at an acute angle toward the bottom wall of the barrel. The annular flange 11 is relatively thick, for example 30 mils, and is quite narrow or short as measured in a plane including the axis of the barrel for example one-eighth inch, so that it is relatively stiff. The outside diameter of the outer edge 13 of the annular flange is from 5 to 20 mils greater than the inside diameter of the bore of the vial so the deflection of the flange 1 1 results in adequate pressure between the edge 13 and the bore of the barrel so that the syringe can be shipped assembled and filled with the fluid to be dispensed. The outer edge of the flange 11 is not feathered so that adequate sealing pressure is built up by deflection of the flange to maintain the seal under static conditions. When fluid is being dispensed, the hydraulic pressure entering the groove 14 between the flanges 9 and 11 augments the sealing pressure. The end wall 8, flanges 9, 11 and junction 15 between the flanges comprise the piston. The junction 15 between the flanges 9 and 11 is joined to a cylindrical wall or plunger 16 which has a loose sliding fit in the barrel 1. The outer flange 17. A rigid support for the cannula 4 is provided by a plurality of axially extending ribs 18 having inner ends 19 joined to the end wall 8 and having inner and outer edges 20 and 21 joined respectively to the outer surface of the cannula 4 and the inner surface of the cylindrical wall 16.

All of the parts of the syringe are adapted to molding from plastic in simple molds resulting in low cost, high speed manufacture so the syringe may be used only once and thrown away, The particular syringe shown was designed to hold a fluid for the treatment of Mastitis.

The flexible plastic flange 11 has no tendency to stick to the barrel and does not require lubrication, an important advantage in syringes which are to be shipped assembled and filled.

What is claimed is:

1. A syringe comprising a barrel closed fluid tight at one end and open at the other end, and a single piece of flexible plastic which forms the seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed and constitutes a cannula, piston and plunger,

said cannula having a fluid receiving end presented to the closed end of the barrel and a fluid discharging end extending out through the open end of the barrel, said plunger having one end. outside the open end of the barrel and the other end inside the barrel,

said piston having an end wall at the other end of the plunger integral with said fluid receiving end of the cannula and a peripheral flange extending from said end wall back toward the open end of the barre] and an annular flange having its inner edge integral with said peripheral flange, said flange diverging from said peripheral flange toward the closed end of the barrel at an acute angle and having sliding contact with the bore of the barrel,

said seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed resulting from the outside diameter of the outer edge of said flange being greater than the in side diameter of the bore of the vial and said flange being stiff enough so the deflection of the flange by static engagement of the outer edge of the flange and the bore results in adequate sealing pressure between the outer edge of the flange and the bore of the barrel to provide and maintain a leak proof seal under static conditions so that the syringe can be shipped assembled and filled with the fluid to be dispensed, the essential stiffness of the flange and sealing pressure under static conditions being obtained when said flange is thick and narrow and has a thick non feathered outer edge of outside diameter greater than the bore of the barrel,

and removable means on and closing the fluid discharge end of the cannula.

2. The syringe of claim 1 having longitudinal ribs sur rounding and fixed to said cannula.

3. The syringe of claim 2 in which said ribs have longitudinal edges fixed to a cylindrical wall.

4. The syringe of claim 1 in which the barrel is prefilled with the fluid to be dispensed and the fluid receiving end of the cannula is at all times in communication with said fluid.

5. A syringe comprising a barrel closed fluid tight at one end and open at the other end, and a single piece of flexible plastic which forms the seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed and constitutes a cannula, piston and plunger,

said cannula having a fluid receiving end presented to the closed end of the barrel and a fluid discharging end extending out through the open end of the barrel,

said plunger having one end outside the open end of the barrel and the other end inside the barrel,

the piston having an end wall. at the other end of the plunger integral with said fluid receiving end of the cannula and an annular flange having its inner edge integral with the periphery of said wall, said flange diverging from the periphery of said wall toward the closed end of the barrel at an acute angle and having sliding contact with the bore of the barrel,

the plunger having axially extending ribs projecting from said cannula, said ribs having ends joined to said bottom wall and having longitudinal edges joined to said cannula,

said seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed resulting from the outside diameter of the outer edge of said flange being greater than the inside diameter of the bore of the vial and said flange being stiff enough so the deflection of the flange by static engagement of the outer edge of the flange and the bore result in adequate sealing pressure between the outer edge of the flange and the bore of the barrel to provide and maintain a leak proof seal under static conditions so that the syringe can be assembled and filled with the fluid to be dispensed, the essential stiffness of the flange and sealing pressure under static conditions being obtained when said flange is thick and narrow and has a thick non feathered outer edge of outside diameter greater than the bore of the barrel, and removable means on and closing the fluid discharge end of the cannula.

6. The syringe of claim 5 in which the plunger has a cylindrical wall slidably fitting the barrel and having its end inside the barrel integral with the cannula and the longitudinal edges of said ribs joined to said cylindrical 

1. A syringe comprising a barrel closed fluid tight at one end and open at the other end, and a single piece of flexible plastic which forms the seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed and constitutes a cannula, piston and plunger, said cannula having a fluid receiving end presented to the closed end of the barrel and a fluid discharging end extending out through the open end of the barrel, said plunger having one end outside the open end of the barrel and the other end inside the barrel, said piston having an end wall at the other end of the plunger integral with said fluid receiving end of the cannula and a peripheral flange extending from said end wall back toward the open end of the barrel and an annular flange having its inner edge integral with said peripheral flange, said flange diverging from said peripheral flange toward the closed end of the barrel at an acute angle and having sliding contact with the bore of the barrel, said seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed resulting from the outside diameter of the outer edge of said flange being greater than the inside diameter of the bore of the vial and said flange being stiff enough so the deflection of the flange by static engagement of the outer edge of the flange and the bore results in adequate sealing pressure between the outer edge of the flange and the bore of the barrel to provide and maintain a leak proof seal under static conditions so that the syringe can be shipped assembled and filled with the fluid to be dispensed, the essential stiffness of the flange and sealing pressure under static conditions being obtained when said flange is thick and narrow and has a thick non feathered outer edge of outside diameter greater than the bore of the barrel, and removable means on and closing the fluid discharge end of the cannula.
 2. The syringe of claim 1 having longitudinal ribs surrounding and fixed to said cannula.
 3. The syringe of claim 2 in which said ribs have longitudinal edges fixed to a cylindrical wall.
 4. The syringe of claim 1 in which the barrel is prefilled with the fluid to be dispensed and the fluid receiving end of the cannula is at all times in communication with said fluid.
 5. A syringe comprising a barrel closed fluid tight at one end and open at the other end, and a single piece of flexible plastic which forms the seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed and constitutes a cannula, piston and plunger, said cannula having a fluid receiving end presented to the closed end of the barrel and a fluid discharging end extending out through the open end of the barrel, said plunger having one end outside the open end of the barrel and the other end inside the barrel, the piston having an end wall at the other end of the plunger integral with said fluid receiving end of the cannula and an annular flange having its inner edge integral with the periphery of said wall, said flange diverging from the periphery of said wall toward the closed end of the barrel at an acute angle and having sliding contact with the bore of the barrel, the plunger having axially extending ribs projecting from said cannula, said ribs having ends joined to said bottom wall and having longitudinal edges joined to said cannula, said seal to the barrel required for shipping the syringe assembled and filled with the fluid to be dispensed resulting from the outside diameter of the outer edge of said flange being greater than the inside diameter of the bore of the vial and said flange being stiff enough so the deflection of the flange by static engagement of the outer edge of the flange and the bore result in adequate sealing pressure between the outer edge of the flange and the bore of the barrel to provide and maintain a leak proof seal under static conditions so that the syringe can be assembled and fIlled with the fluid to be dispensed, the essential stiffness of the flange and sealing pressure under static conditions being obtained when said flange is thick and narrow and has a thick non feathered outer edge of outside diameter greater than the bore of the barrel, and removable means on and closing the fluid discharge end of the cannula.
 6. The syringe of claim 5 in which the plunger has a cylindrical wall slidably fitting the barrel and having its end inside the barrel integral with the cannula and the longitudinal edges of said ribs joined to said cylindrical wall. 